Control mechanism for spraying devices



April 5 T. G. NYBORG 2,705,473

CONTROL MECHANISM FOR SPRAYING DEVICES Filed April 2'7, 1951 2 Sheets-Sheet 1 Z2 5 6 7 5 7 I Q w a 20 19 g mmmm i 9 L 0 i v 'i 2; 111

April 5, 1955 Filed April 27. 1951 T. G. NYBQRG CONTROL MECHANISM FOR SPRAYING DEVICES 2 Sheets-Sheet 2 face/z 507 face G. @5

United States Patent CONTROL MECHANISM FOR SPRAYING DEVICES Tage Georg Nyborg, Worcester, England, assignor of onehalf to The Mining Engineering Company Limited Application April 27, 1951, Serial No. 223,295

Claims priority, application Great Britain May 2, 1950 7 Claims. (Cl. 118-8) In mining practice it is customary to use water sprays at points where the mined material is transferred from one means of transport to another or to a bunker in order to allay dust. Such points, for example, may be where a gate belt conveyor discharges on to a trunk or gathering belt conveyor or where a trunk belt conveyor discharges into mine tubs.

It is highly desirable that such water sprays should only operate when the transport system is operating and when it is actually transporting broken mineral otherwise excessive moisture is deposited on the belt or the like.

In apparatus according to the present invention the spray is controlled by apparatus embodying a closed fluid circuit the pressure in which is sensitive both to motion of the transporting means and to the presence of material carried on the transporting means, so that a sufficiency of material must be actually moving at a selected point in order to establish the pressure condition in the closed control circuit which will cause spraying to take place.

According to one part of the invention there is a pump driven from the conveyor belt or the like and pumping fluid from a reservoir to a chamber where its pressure will cause a valve controlling the water spray to open and the fluid to circulate back to the reservoir while maintaining the pressure, in combination with a by-pass valve or equivalent upon operation of which the fluid from the pump can be returned to the reservoir with insufficient pressure to cause or maintain the opening of the valve controlling the water spray.

The by-pass valve can be operated in any appropriate manner in accordance with the actual loading of the transporting means; but it may alternatively or additionally be operable manually, so that an attendant can regulate or stop the spray by means of the by-pass valve.

A simple preferred form will now be described by way of example with reference to the acompanying drawings, in which:

Fig. 1 is a plan view of the device,

Fig. 2 is a vertical section on the line II--II of Fig. l. Fig. 3 is a horizontal section on the line Ill-III of Fig. 2,

Fig. 4 is a view on the line IV--IV of Fig. 1 with certain parts omitted,

Fig. 5 is a partial section on the line V-V of Fig. 1 showing modified non-return pump ports and an adjustable leak-o5 valve.

As shown in the drawings the control valve has a body 1 incorporating a reservoir 2.

The upper part of the body provides connections 3 and 4 for the inlet and outlet of pressurized spray water, and cylinders 5 and 6 for a piston valve 7 and its operating piston 8.

The piston valve 7 is normally held closed by a spring 9 and can be moved to uncover the port of the inlet 3 on admission of pressure to the cylinder 6 behind the piston 8, as will be later described.

The reservoir 2 normally contains oil or other suit able liquid, and a gear pump comprised by the gears 10 and 11 is fitted in a filler plate 12 (Fig. 4). The gear pump is driven through a shaft 13 from a roller in contact with the conveyor belt or tub cable with which the control valve is associated.

The pump is arranged to operate for either direction of rotation of the shaft 13 and to this end it is provided with a pair of suction ports 14 (Figs. 3 and 4) and a pair of discharge ports 15 (Figs. 4 and 5); each port is fitted with a non-return valve.

The suction ports 14 are in direct communication with the reservoir 2 and the discharge ports communicate with an inlet port 16 to the cylinder 6 through a passage 17 (Figs. 2 and 5) provided in an end face of the body 1.

A branch 18 from the passage 17 leading back to the reservoir 2 is controlled by a valve 19 (Fig. 2).

This by-pass valve 19 is normally held seated by a spring 20 and has an extended spindle 21.

The extended spindle 21 may be arranged for manual operation or may be also connected for operation through a lever linkage system pivoted to the boss 22 and sensitive to the absence of load from the associated conveyor or to the absence of tubs from a tub loading point.

A port 23 vents the forward end of cylinder 6 back to the reservoir 2 and a port 24 is opened on a forward movement of the piston 8 to permit a. circulation of oil when the piston is in the position to open the valve 7.

The leak-otf valve illustrated in Fig. 5 is connected in parallel with the by-pass valve 19 and acts to permit a small circulation of oil under all conditions whenever the gear pump is running and to vent air from the pump on starting. It consists of a small hollow stem 25 having a head 26 urged outwardly by a spring 27.

An elongated port 28 in the stern can be opened to a required degree by adjustment of a screw 29 which is locked by a nut 30.

It will be noticed that the non-return valves fitted in the ports 14 and 15 are shown in this figure modified by the omission of springs.

In operation the shaft 13 is driven in one direction or the other by the belt or cable with which the control valve is associated. The shaft 13 drives the gear pump 10, 11 which takes liquid through one or other of ports 14 from the reservoir 2.

Pressure fluid discharged by the pump flows to the port 16 through the channel 17 and shifts the piston 8 and valve 7 to a position giving a free flow of pressurized spray liquid between connections 3 and 4.

Should there be no load on the conveyor, or no tub at the tub loading point to be sprayed the lever linkage connected to the spindle 21 will be operated to open the valve 19 and permit a free by-pass of pressure fluid from the gear pump 10, 11 back to the reservoir 2. Under these circumstances insuflicient pressure will build up behind piston 8 to operate the valve 7 and no spray will occur.

It will be understood that the single automatic valve controlling the spray jet can only permit it to operate when the conveyor belt is driving the pump and when the by-pass valve is permitted to close under the influence of its spring by the presence of mined material on the conveyor or a mine tub acting on any suitable system of control levers. Furthermore a manual control on the by-pass valve may hold it open to stop the spray jet when desired.

While one form has been described by way of example it will be appreciated that various. other arrangements are possible embodying a closed fluid circuit, the pressure in which is used to regulate the water spray so that it will be cut off either when the transporting means is stationary or when it is in motion but no load is being carried.

I claim:

1. A mining water-spray control valve comprising in combination a liquid reservoir, a pump adapted to be driven by load transporting means and having an inlet port opening in communication with said reservoir, a closed hydraulic circuit to which the pump delivers, a by-pass valve normally spring urged to a closed position between the circuit and the reservoir and adapted for operation by means sensitive to the absence of load on the load transporting means for operating the bypass valve, and an hydraulically operated valve operable by a sufficiency of pressure in the circuit to open a passage between a spray-water inlet and outlet.

2. A spray control mechanism for use with a load transporting means, said mechanism comprising a casing provided with a reservoir, a pump adapted to be operated in response to actuation of the transporting means,

said pump having an inlet in communication with said reservoir, a closed hydraulic circuit into which said pump delivers and including a normally closedby-pass valvebetween the circuit and reservoir, means responsive to an external stimulus to actuate said by-pass valve thereby governing the fluid pressure in said circuit,.'and valve means connected with said casing and adapted to control flow from a supply of spray liquid, said valve means being operable in response to changes in pressure in said circuit.

3. A spray control mechanism as defined in claim 2 including an adjustable leak-01f valve between said hydraulic circuit and said reservoir to permit a small flow of hydraulic fluid under all conditions of pump operation.

4. A mining water spray control assembly comprising a casing, a pump carried by the casing, means to actuate said pump, a reservoir communicating with the inlet oi said pump, a cylinder in said casing, a valve member in said cylinder for controling the flow of spray water, an outlet port for said pump, a passage in said casing connecting said outlet port with said cylinder so that said valve member is operable in response to fluid under pump pressure that passes through said passage, a branch passage in said passage opening into said reservoir to relieve the pressure in said passage thereby influencing the actuation of said valve member, and means responsive to an external stimulus for opening said branch passage to thereby further influence the actuation of said valve member.

5. An assembly as defined in claim 4 wherein said branch passage opening means consists of a normally closed by-pass valve, and resilient means connected with said valve member and yieldingly opposing the fluid pressure actuation of said valve member.

6. An assembly as defined in claim 5 and including a leak-off valve connected in parallel with said normally closed by-pa-ss valve, said leak-off valve being continually open at least a small amount to permit small circulation any time that said pump is operative.

7. A spray control mechanism for controlling the flow of spray liquid to a conventional mining spray element, said mechanism comprising a hydraulic fluid reservoir, a pump communicating therewith to draw hydraulic fluid therefrom, a control valve adapted to be actuated by hydraulic fluid under pump pressure, means responsive to an external stimulus for varying the pressure of the hydraulic fluid that ultimately reaches said control valve and including aby-pass valve, a closed hydraulic circuit in which said by-pass valve is disposed downstream of said pump and upstream of said control valve, said bypass valve having a spring normally closing the same, and the control valve having ports, one of which vents the same and the other of which opens into said reservoir to permit a return flow of hydraulic fluid in response to a predetermined movement of said control valve.

References Cited in the file of this patent UNITED STATES PATENTS 642,135 Koch et a1. Jan. 30, 1900 1,827,876 Lang Oct. 20, 1931 1,940,269 Pierce Dec. 19, 1933 2,229,725 Cheaslcy Jan. 28, 1941 2,443,414 Burt-Wells June 15, 1948 OTHER REFERENCES Report of Investigations No. 3843 by U. S. Bureau of Mines, November 1945, Fig. 26. 

